Kernel Vulnerability in Linux Package: Zero Initialization Flaw in netdevsim
Summary
DEBIAN-CVE-2026-52985: In the Linux kernel, the following vulnerability has been resolved: netdevsim: zero initialize struct iphdr in dummy sk_buff Syzbot reports a KMSAN uninit-value originating from nsim_dev_trap_skb_build, with the allocati... Affects linux versions 5.10.103-1 – 7.1~rc7-1~exp1. No fix is published. How to fix ↓
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Background
The Linux kernel is a core component of many operating systems, providing essential services for hardware management and system processes. It is known for its robustness and flexibility, supporting a wide range of devices and architectures. However, vulnerabilities can arise, such as the one identified in the netdevsim module, which simulates network devices for testing purposes. This specific vulnerability relates to improper initialization of data structures, potentially leading to undefined behavior.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified in the netdevsim module where the struct iphdr is not zero-initialized in the dummy sk_buff. This flaw was reported by Syzbot, indicating a KMSAN uninitialized value originating from the nsim_dev_trap_skb_build function. The lack of proper initialization can lead to unpredictable behavior and security risks, as uninitialized memory may contain sensitive data or cause crashes.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can manually ensure that the skb_put_zero function is used instead of skb_put in their implementations to guarantee zero initialization of the IP header, although this requires code modification.
Conclusion
The vulnerability in the Linux kernel's netdevsim module highlights the importance of proper memory initialization to prevent security risks. Users are encouraged to update their systems to the patched versions to ensure safety and stability. Utilizing tools like Vulert can help in monitoring and managing vulnerabilities effectively.
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FAQ
The vulnerability involves improper initialization of the IP header in the netdevsim module of the Linux kernel, which can lead to undefined behavior.
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The risks include unpredictable behavior of the network simulation, potential crashes, and exposure of sensitive data due to uninitialized memory.
Yes, patches are available for Debian 13 and Debian 14. Users should update to the specified fixed versions to mitigate the vulnerability.
If immediate updates are not possible, consider implementing the workaround by ensuring proper initialization in your code.
References
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